/*
 * Copyright (C) 2008 feilong
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.feilong.excel.writer;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.CellType;
import org.apache.poi.ss.usermodel.DateUtil;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;

class CellStyleSetter{

    /** Don't let anyone instantiate this class. */
    private CellStyleSetter(){
        //AssertionError不是必须的. 但它可以避免不小心在类的内部调用构造器. 保证该类在任何情况下都不会被实例化.
        //see 《Effective Java》 2nd
        throw new AssertionError("No " + getClass().getName() + " instances for you!");
    }

    //---------------------------------------------------------------

    /**
     * 设置 cell style.
     *
     * @param sheet
     *            the sheet
     * @param rowIndex
     *            the row index
     * @param cellIndex
     *            the cell index
     * @param cellStyle
     *            the style
     */
    static void set(Sheet sheet,int rowIndex,int cellIndex,CellStyle cellStyle){
        if (cellStyle == null){
            return;
        }

        //---------------------------------------------------------------
        Row row = sheet.getRow(rowIndex);
        if (row == null){
            row = sheet.createRow(rowIndex);
        }
        Cell cell = row.getCell(cellIndex);
        if (cell == null){
            cell = row.createCell(cellIndex);
        }

        //---------------------------------------------------------------
        CellStyle currentCellStyle = cell.getCellStyle();
        if (currentCellStyle == null || (cell.getCellType() != CellType.NUMERIC) || (!DateUtil.isCellDateFormatted(cell))
                        || DateUtil.isADateFormat(cellStyle.getDataFormat(), cellStyle.getDataFormatString())){
            cell.setCellStyle(cellStyle);
        }else{
            CellStyle newCellStyle = sheet.getWorkbook().createCellStyle();
            newCellStyle.cloneStyleFrom(cellStyle);
            newCellStyle.setDataFormat(currentCellStyle.getDataFormat());
            cell.setCellStyle(newCellStyle);
        }
    }
}
